Many particulate materials such as powdered detergent, powdered bleach, and other industrial products are used in measured amounts. For example, a measured quantity of powdered detergent is often used when washing clothing. To access the powdered detergent, a user opens a powdered detergent box and digs his hands through the caustic detergent to locate a scoop for dispensing the detergent. This approach has several drawbacks. First, the user's skin is exposed to the caustic detergent. Second, a powdered detergent box typically can't be resealed after it is opened. As a result, clumps of detergent may begin to form due to the detergent's exposure to the surrounding environment. Therefore, there is a continuing need for a dispenser that permits a particulate material container to be resealed after use and prevents a user from being exposed to the particulate material while the particulate material is being measured and dispensed.
Another drawback encountered in the prior art is that some particulate materials that should be used in measured amounts are not accompanied by a precise measuring device. For example, different sized pets require different quantities of pet food. However, conventional pet food containers either have no measuring and dispensing device (the food being dispensed from an opening in the food container) or a generic "one size" dispensing device (such as a scoop). This leads to a number of drawbacks. First, the pet food is exposed to the surrounding environment if the food is being dispensed through an aperture torn, cut, or otherwise permanently made in a surface of the container. Second, the pet may be overfed or underfed depending on the relationship between the size of the pet and the size of the generic scoop.
A few inventions have attempted to overcome the drawbacks encountered in the prior art. U.S. Pat. No. 3,921,862 to Holmstrom is directed to a measuring pour spout for installation on a detergent carton or box. Although the Holmstrom spout reduces the likelihood that a user will be exposed to the material within the carton or box, the Holmstrom spout has a number of limitations. First, the Holmstrom spout relies on a plastic frame and more than one moving part to allow a user to adjust the quantity of the detergent that is measured and dispensed. These features make the Holmstrom spout far too expensive to replace the current laundry detergent scoops now included in detergent cartons or boxes. Second, the Holmstrom spout is filled with detergent while the spout is positioned within the detergent carton or box. Therefore, a user cannot see when the Holmstrom spout is filled with a measured quantity of detergent. As a result, a user may dispense detergent using the Holmstrom spout before the spout is completely filled with the correct amount of detergent. Third, there are at least five steps required for measuring and dispensing detergent using the Holmstrom spout. This represents no significant reduction in time or work over the conventional measuring and dispensing processes discussed above. Therefore, a user is unlikely to use the Holmstrom spout for the few benefits it provides.
U.S. Pat. No. 4,637,529 to Knight is directed to a measuring dispenser for particulate material. Although the Knight dispenser is simpler and cheaper to mass produce than the Holmstrom spout, the Knight dispenser also has a number of limitations. First, the Knight dispenser does not permit a user to adjust the measured amount of detergent to be dispensed. This is a significant limitation since a user will often desire to adjust the amount of detergent being dispensed. For example, a user will want to measure and dispense a smaller amount of detergent for a light load of laundry than the user would want to measure and dispense for a heavy load of laundry. Second, the Knight dispenser, like the Holmstrom spout, also fills with detergent while the dispenser is positioned within the detergent carton or box. Therefore, a user cannot see when the Knight dispenser is filled with a measured quantity of detergent. As a result, a user may dispense detergent using the Knight dispenser before the dispenser is completely filled with the correct amount of detergent. Third, a closure panel or gate is used in the Knight dispenser to stop the dispenser from overfilling after the dispenser has been filled with a measured quantity of detergent. However, the closure gate may not always close properly since the gate is designed to close while the detergent is filling the dispenser. In other words, the flow of the particulate detergent may impede the closure of the gate after the dispenser has been filled with a selected quantity of detergent.
U.S. Pat. No. 4,144,989 to Joy, and U.S. Pat. No. 5,002,208 to Towery, are directed to dispensers for measuring and dispensing particulate material. However, these dispensers suffer from the limitations discussed above and are complex devices that are not cost effective. More particularly, the dispensers cannot be incorporated into a particulate container production line inexpensively enough to compete with the conventional scoops provided in the particulate containers of the prior art.